It’s early morning in Krasnoyarsk Krai, Russia on the 30th of July 1908. There isn’t a cloud in the sky and the morning is already hot and dry in the isolation of the Siberian wilderness. The day starts just as any other would when suddenly, at around 07:17am, the sun is not the only object in the Russian sky. Something else has appeared. Described by eyewitnesses as being a “blue-ish-white” colour, the object hurtled through the atmosphere leaving a dark, dusty trail behind it. As the object gets closer it becomes increasingly bright until it matches, then surpasses the light intensity of the sun. The trail cuts the sky in half as it descends lower through the atmosphere until it reaches approximately three to six miles above the Earth’s surface where it explodes in what’s known as an air burst. This explosion is regarded as the largest impact event in recorded history even though technically there wasn’t actually any contact made between the ground and whatever it was that fell out the sky on that day.

The explosion registered on meteorological instruments and in seismic stations worldwide and caused atmospheric fluctuations in pressure strong enough to be detected 3530 miles away in Britain. It also caused the night skies across much of Eurasia to have a strange glow for several weeks after the event. Trees at ground zero were left standing but stripped of their leaves and branches by the downward force of the blast shockwave as it exploded in the air. Trees slightly further out where uprooted and flattened by the more horizontal shockwave after it had travelled downwards toward the ground and then dispersed across it. It has been estimated that the size of the explosion was anywhere between that of 3-30 megatons with 10-15 megatons being the best guess. To put that into perspective that would be a thousand times bigger than the atomic bomb dropped on Hiroshima and around about two fifths of the size of the largest thermonuclear device ever detonated, the former Soviet Union’s Tsar Bomba.

The damage was spread across an area of around 849 square miles and between 60-80 million trees were uprooted or downed, there was even a case in which a man 40 miles away was knocked of his feet by the shockwave. Officials have estimated that the event would have registered as a five on the Richter scale if the scale had been around at those times and had it occurred in larger more metropolitan area could have completely wiped it out. But what was it that fell out of the sky? Initially there was little interest in the event from the scientific community, possibly due to it’s remote location and, if there had been any early expeditions, the likelihood is that they would have been lost in Russia’s subsequently chaotic years. The first recorded expedition to the sight was more than a decade after the explosion’s occurrence. Russian mineralogist Leonid Kulik convinced the Soviet government to fund an expedition into the area on the assumption that there had been a meteor impact and that there was the possibility of meteoric iron to be salvaged and used to aid Soviet industry. The group departed in 1927. Upon his arrival at the site Kulik observed the utter devastation for himself and since then many more expeditions to the site have occurred, many with conflicting views upon what actually happened there. Kulik himself believed that the explosion had been caused by a massive meteorite impact after hearing the accounts of local people during his expeditions but others have gone on to argue even more exotic explanations as to what actually occurred.

Lets take a look at a few of them.

Asteroid/Comet

This is the most popular theory amongst scientists and geologists and there is ample evidence at the site of the explosion that points towards this scenario. This includes mineral samples that show high levels of nickel relative to iron, which is very common in meteorites, as well as high levels of iridium, which is also found in meteorites. As asteroids usually enter Earth’s atmosphere at speeds of at least six to seven miles per second, this causes immense heat and pressure to build up due to the compression of the air in front of the body and most usually explode before they hit the ground. As you would expect, the size of the asteroid dictates the size of the explosion it causes so if this is what happened it must have been a fairly large hunk of space rock. Another theory that runs in the same vein as the asteroid/comet theory is that of a natural H-bomb. This idea suggests that a comet with an anomalously high level of deuterium in its composition could have undergone a nuclear fusion reaction upon entering the atmosphere. However, studies have shown this to be inconsistent with evidence found at the site as well as being inconsistent without our knowledge of what comets are made of and also the conditions required for triggering a thermonuclear reaction.

Black Hole

In 1973 it was proposed by two physicists by the names of Albert A. Jackson and Michael P. Ryan, that the Tunguska event had actually been caused by a tiny black hole passing through the Earth. The scientific community does not accept this as it does not explain the material deposited by the extra-terrestrial body. Also, if it had been a black hole passing through our planet where was the exit event? Based on the calculated direction of impact the exit event would have occurred somewhere in the north Atlantic, closer to the instruments of the seismic stations that had accumulated much of the evidence of the original blast. There is no recorded evidence of this happening. It is also not known with any certainty whether black holes can exist in a subterranean environment, as we have no known occurrences of this type. Black holes are typically found when a giant star collapses in on itself and implodes at the end of its life causing a gravitational singularity. Supermassive black holes are usually found in the centres of galaxies and are much bigger.

Natural Gas Explosion

Proposed by astrophysicist Wolfgang Kundt, this idea speculates that the Tunguska event was actually caused by the displacement of natural gas. Again, this version of events doesn’t solve the mystery of the cosmic material found at the site nor does it align with witness testimony collected at the time. The size of the explosion would mean that at least 10 million tons of natural gas would have had to have been released from beneath the Earth’s crust and subsequently explode causing the extreme damage found in the area. The similar Verneshot hypothesis (an underground volcano caused by the build up of natural gas) has also been suggested as the cause of the event yet neither are currently accepted as being the probable cause by the scientific community at large. However, this scenario could explain the crater like depressions found at the Tunguska site and it is possible that gas displacement may have caused a caldera-like effect causing small craters to be formed in certain areas of the blast site as found by Kulik on his expeditions.

Antimatter

Antimatter is the mirror opposite of all the regular matter that we see around us. When normal matter and antimatter come into contact they annihilate each other in an explosive conversion of all the energy stored in their respective particles. This conversion of energy is as 100% efficient as Einstein’s E=mc2 calculation. This idea speculates that the event may have been caused by a chunk of antimatter falling towards the Earth and annihilating when it came into contact with the normal matter particles that provide us with an atmosphere. This theory is considered flawed as it is extremely unlikely that the amount of antimatter required for this type of explosion would have been able to travel through interstellar space without coming into contact with regular matter before it met us. It also does not explain the extra-terrestrial material found at the site as this surely would have been annihilated along with the rest of the matter/antimatter on impact.

Nikola Tesla and his “Death Ray”

This theory is interesting enough to have it’s own article let alone feature in this one. For the few who don’t recognise the name from school, Tesla was arguably one of the greatest minds of the late nineteenth and twentieth centuries. Known for his experimentation with electricity and countless conspiracy theories involving the suppression of free energy, Tesla was also allegedly involved in building a giant death ray, a transmitter that was capable of projecting the force of an atomic explosion via radio. As far out and outlandish as that may sound Tesla had already had some links with the military as he had previously offered them a kind of wireless torpedo he called a Telautomaton. This device was likened to a remote control boat that would have been used to carry explosives to enemy naval targets; an airborne version was also supposedly under development. The idea that Tesla had carried out a test of his death ray and caused the Tunguska explosion has never been given much attention by scientists studying the event, possibly because of it’s rather conspiracy orientated roots.

There is in fact much more speculative conjecture being thrown around in places such as internet chat rooms, blogs and websites dedicated to the subject as well as other mysterious and paranormal magazines, all of whom are guaranteed to have their own ideas based on the evidence they have collected themselves. Among some of the crazier ideas I came across were that of an eighteenth century Japanese alien spacecraft crash landing in Siberia, a “terrestrial geological entity” causing destruction on the planet’s surface due to a to desire punish mankind.

As extreme as these may be they were not the only ones, others included Soviet time travel, alien attack/invasion and all kinds of typical, badly thought through conspiracy theories regarding an Illuminati or other mysterious and insidious groups. Whether you believe in alien intelligence or not the idea that UFO’s have crashed into Earth is always plausible however unlikely it may sound. If you assume aliens exist how much further do you have to go to assume they would have developed advanced positioning systems aboard whatever vessel they were travelling in to avoid that kind of incident? Not very far surely? I myself believe in extra-terrestrial intelligence but that it would come with exactly that, intelligence.

As you can imagine with something that happened over a century ago there has been plenty of time for scientists and civilians alike to devise more and more models on what could have happened all those years ago. With more and more ever advancing technology becoming available it may still one day be possible to predict exactly what happened over one hundred years ago but as of yet this particular mystery still evades certainty. Many will argue that evidence at the scene points towards the asteroid/comet theory as being the most prominent and likely to have occurred yet there are still many that will oppose this judgement on the basis that at this moment in time we just cannot be sure.

Recent expeditions to the site by various different groups of researchers have themselves stated that the possibility of an air burst due to asteroid or comet does seem most likely situation to produced the evidence that is or was available as it is the only theory that answers, if only partially sometimes, the questions asked. However, as of yet there are still too many questions yet to have definitive answers for anyone to say with authority what actually caused the Tunguska event and until those get answered we can predict only that the mystery will live on in the minds of the people who wish to truly understand what happened.

This is very interesting indeed. There are a few unexplained stories like this, I once saw a great video which collected them, I tried to find it to post here but can’t find the link. Great article, thanks.

Ryan Morwood

I’m glad you enjoyed it. I’d encourage you to take a peak at some of the other theories about this I didn’t fully explain as some of them are really quite elaborate and also pretty hilarious.

LITOSWEED

It was electric discharge before impact, just like when NASA hit that comet with that copper projectile. There was a huge flash explosion then the projectile hit.